The exhaust I have on my truck which is a Magnaflow X with dual Magnapack mufflers, is way big for this motor. I posted a 17 RWHP loss over my old system. If you had more restrictive mufflers you would be alright, maybe, but the Magnapacks are straight through. No back pressure at all! My custom exhaust traps have saved me though. Last night with my setup I ran a 14.371 @ 95.57!

When I got my Magnacharger, I took a delay on the order to get the new manifold which should fit the PI heads mentioned above. I will build a motor before too long with all forged internals and stage II blower heads. If I have manifold problems, then I will get a new Manifold from Magnacharger!......I hope!

 

Nice run Flats Man!! You're getting faster all the time! Congratulations on running a 14.3,,,,98

 

The million dollar question now is. So which muffler is going to produce enough backpressure to substain or increase torque and HP, yet I repeat yet still sound killer? This may be a tall order to fill. I am sure you would get some looks going into a muffler shop and saying "Give me your most restritive muffler", they're probably going to laugh, then pull that old, rustly, clogged one off Billy-Joe Bob JR's Pinto out of the dumpster.

 

Or they might just sell you another stock F-150 muffler, and then dual it, LOL!,,,,98

 

98
Your probably right. Kinda defeats the whole purpose. I mean why spend 400+ to wind up with a 200+ sounding system that has helped you gain little if any HP or torque. I like the idea and the looks of the x-pipe. In my mind it should be the perfect setupbut since Flats review I have other thoughts. We will have to see what we can figure out?

 

Don't get me wrong, the X-pipe has been proven to gain HP in several magazine aticles I've seen. Over doing flow, ie: pipe size, high flow mufflers, etc.. will kill low end torque! The same system with say, turbo mufflers, might have had a entirely different effect. Engines are touchy about exhaust and intake flow, plain and simple Have you ever known someone who put an 1150 dominator carb on a small block, it bogs the engine down.,,,,98

 

Well Boys, I am up to something that will use up some more of that big exhaust on my truck. I am very happy with the traps for right now and they saved me at FFW in Orlando this weekend. We had about 20 to 25 knots of wind right down the middle of the track so I set up for maximun torque, folded my mirrors down and punched holes through that wind for two days! Sixpipes is driving my Truck in the event and we are still in Top Truck after the first round thanks to a red light from a Lightning. You may not know but Steve Grebeck was killed on the track yesterday which closed the event. We will continue the event in Atlanta in April. I have until then to completely change the tune on the little 4.6L, More later............

 

Hello Flats Man. First off let me say that I'm very sorry to hear about Mr. Grebeck's untimely demise.

Like many others I've been following this thread closely. What a tease you are! Your last reply brings up so many questions but I'll take a stab at just one.

What do you have planned to utilize the full diameter of your exhaust system?

BTW, a big congratulations on the great results of your latest 1/4 mile campaign! And let me say once again that myself and others really appreciate you sharing the fruits of your labors with the rest of us. You're a pioneer of sorts and I thank you.

 

Thanks Lepew, for your kind words. I will be doing a major retune of the truck and I will share it with everyone as usual. I hesitate to go into it too much because I would not want anyone to be lead in the wrong direction on this. Two of the changes will be NKG 5 plugs, and a 170 degree thermostat, and another change will be a Lightning 80 mm MAF instead of my Pro M. The other changes, I will announce if they turn out to work properly.
This time around, I will plan on tuning the chip in the truck at the track under real conditions. I am not getting rid of the Pro M because I am unhappy with it. It is a great MAF and I have had very good results with it. I am so far out on the edge that I need more flexibility in my tuning parameters so I need a MAF that can be controlled by a chip. The Pro M has to be calibrated by Pro M and I can't change the voltage settings etc. If anyone is interested, I will sell my Pro M 80 at 1/2 retail and it is already calibrated for 19 lb injectors.
With my Brother, Sixpipes driving, we made it through the first round at FFW on Sunday when the Lightning next to us red lighted. We will be going to Atlanta in April where the race will be continued. That is my target date to get all these mods done . I attached a picture of the Lightning and my truck staged at FFW.
Sorry about showing up as Sixpipes. I just took him to the airport for his flight back to Texas and he was still logged in on my computer. This is Flats Man......honest!